Single antenna elements, antenna arrays, and antenna systems utilize radomes to protect the antenna components (which may include an antenna and related circuitry). The radome shields the antenna components by preventing objects on one side of the radome from reaching the antenna components that are located on another side of the radome. For example, the antenna components may be protected by a radome from the vagaries of people and/or weather conditions.
Radomes designed for outdoor-use must be capable of shedding water from the surface of the radome, particularly when a major surface of the radome is oriented horizontal to the force of gravity. When water exists in the path of the signals emanating from or to the antenna, the signals may be attenuated. For example, when more than about 20% of the radiating area is covered by water, the attenuation can be significant. Signal attenuation makes incoming and outgoing signals difficult to detect and amplify. Furthermore, when water exists in the path of the signal, the center frequency of the antenna system may shift due to the different electromagnetic characteristics of air and water.
In the prior art, a radome having a curved surface is placed over the antenna in order prevent water from contacting the antenna and in order to prevent water from accumulating in the path of the signals traveling to and from the antenna. The curved surface of the prior art is usually spherical in shape—that is to say that many prior art radomes have an external surface that is a portion of a sphere.
The spherical surfaces of existing radomes allow water to run off the radome, but these radomes increase the size of the antenna assembly, thereby causing the antenna assembly to occupy space that could be used by other components, and/or causing the radome to extend further from a surface to which the antenna is mounted. In situations where the antenna components are mounted below the plane of an exterior surface (e.g. for aerodynamic or aesthetic reasons), a spherical radome designed to prevent water accumulation may extend beyond the exterior surface, thereby reducing the benefits of mounting the antenna components below the exterior surface.
Thus, there is a need for a radome that can prevent water from accumulating, while also minimizing the size of the antenna assembly.